18-15
Cisco Catalyst Blade Switch 3120 for HP Software Configuration Guide
OL-12247-01
Chapter 18 Configuring MSTP
Configuring MSTP Features
Default MSTP Configuration
Table 18-4
shows the default MSTP configuration.
For information about the supported number of spanning-tree instances, see the
“Supported
Spanning-Tree Instances” section on page 17-10
.
MSTP Configuration Guidelines
These are the configuration guidelines for MSTP:
•
When you enable MST by using the spanning-tree mode mst global configuration command, RSTP
is automatically enabled.
•
For two or more stacked switches to be in the same MST region, they must have the same
VLAN-to-instance map, the same configuration revision number, and the same name.
•
The switch stack supports up to 65 MST instances. The number of VLANs that can be mapped to a
particular MST instance is unlimited.
•
PVST+, rapid PVST+, and MSTP are supported, but only one version can be active at any time. (For
example, all VLANs run PVST+, all VLANs run rapid PVST+, or all VLANs run MSTP.) For more
information, see the
“Spanning-Tree Interoperability and Backward Compatibility” section on
page 17-11
. For information on the recommended trunk port configuration, see the
“Interaction with
Other Features” section on page 12-20
.
•
All stack members run the same version of spanning tree (all PVST+, rapid PVST+, or MSTP). For
more information, see the
“Spanning-Tree Interoperability and Backward Compatibility” section on
page 17-11
.
•
VTP propagation of the MST configuration is not supported. However, you can manually configure
the MST configuration (region name, revision number, and VLAN-to-instance mapping) on each
switch within the MST region by using the command-line interface (CLI) or through the SNMP
support.
Table 18-4
Default MSTP Configuration
Feature
Default Setting
Spanning-tree mode
PVST+ (Rapid PVST+ and MSTP are disabled).
Switch priority (configurable on a per-CIST port basis)
32768.
Spanning-tree port priority (configurable on a per-CIST port basis)
128.
Spanning-tree port cost (configurable on a per-CIST port basis)
1000 Mb/s: 4.
100 Mb/s: 19.
10 Mb/s: 100.
Hello time
2 seconds.
Forward-delay time
15 seconds.
Maximum-aging time
20 seconds.
Maximum hop count
20 hops.